Bb chevy head casting date help
 

I came across a pair of heads from a buddy of mine.
These are Rec port heads, iron , casting #3919840
They also have what appears to be these numbers
H 23 7 with possibly a 0 or some hump next to the 7
Are these a build date of August 23rd in 1967 ???
Trying to see if they will work for my 1968 build
Thanks :)

Yes Aug. of 67. Usually no more than a 4 week spread between casting date of the heads to casting date of block